Method and system for processing wireless digital multimedia

ABSTRACT

Multimedia from a source can be wirelessly transmitted in a 60 GHz system to a display. To support rapid reads of encryption, EDID, and other data written into a slave at the display by a master at the source in accordance with I 2 C protocol, a master simulator on the display side continually polls the slave for changes, and maintains a shadow memory in a slave simulator at the source side current, so that reads from the master may be immediately executed from the shadow memory in the slave simulator without transmitting the wireless link.

This is a continuation of and claims priority to U.S. patent applicationSer. No. 11/231,052, filed Sep. 20, 2005, now U.S. Pat. No. 7,719,482which in turn claims priority from U.S. provisional app. 60/624,940,filed Nov. 3, 2004, from which priority is claimed.

FIELD OF THE INVENTION

The present invention relates generally to wireless multimediapresentation systems.

BACKGROUND OF THE INVENTION

Digital video can be transmitted from a source, such as a DVD player,video receiver, ATSC tuner, or other computer, to a display, such as aflat panel video monitor, using a protocol known as Digital VisualInterface (DVI). Having been developed primarily for computers, DVI doesnot provide for processing audio data.

Accordingly, to extend communication protocols to digital multimediathat includes audio for the purpose of, e.g., playing digital movies andthe like, a protocol referred to as High Definition Multimedia Interface(HDMI) has been developed. HDMI is similar to DVI except it includes theuse of audio as well as video data. Both DVI and HDMI are intended forwired transmission, and permit the encryption of digital multimediausing an encryption method known as High-Bandwidth Digital ContentProtection (HDCP).

As recognized herein, to provide maximum placement flexibility and easeof installation, it may be desirable to present the multimedia on adisplay using a minimum of wiring. For instance, it may be desirable tomount a projector on the ceiling or to mount a plasma display or liquidcrystal high definition (HD) television display on a wall, out of theway and capable of receiving multimedia data for display without theneed for wires, since as understood herein among other things datatransmission lines often do not exist in ceilings or walls.

The present invention further understands, however, that not just anywireless transmission system will do. Specifically, if a wireless linksuch as IEEE 802.11(b) is used that has a bandwidth which isinsufficient to carry either compressed or uncompressed multimedia suchas uncompressed high definition (HD) video, compressed multimediastandard definition (SD) video would have to be transmitted, requiring arelatively expensive decompression module at the projector. Some linkssuch as IEEE 802.11(a) do have a bandwidth high enough to carrycompressed HD video but not uncompressed SD or HD video. Also, in thecase of 802.11(a) copyright protection may be implicated because thelink is sufficiently long range (extending beyond the room in which itoriginates) that it can be detected beyond the immediate location of thetransmitting source. With this in mind, the present invention recognizesthe need for a limited range, preferably directional, high bandwidthwireless link that is particularly suited for the short range wirelesscommunication of uncompressed multimedia, particularly the rathervoluminous genre of multimedia known as HD video.

The present assignee has provided a wireless system that functions inthe spectrum between 57 GHz and 64 GHz (hereinafter “60 GHz band”).Characteristics of the 60 GHz spectrum include short range, highdirectivity (and, hence, inherent security), and large data bandwidth.The present assignee's co-pending U.S. patent application Ser. Nos.10/666,724, 10/744,903 (systems), Ser. Nos. 10/893,819, 11/136,199(PLL-related inventions), and Ser. No. 11/035,845 (multiple antennae),all of which are incorporated herein by reference, disclose varioussystems and methods for sending high definition (HD) video in HighDefinition Multimedia Interface (HDMI) format from a source in a room toa receiver in the room, using a high bandwidth 60 GHz link. At thisfrequency the signal has very short range and can be directional suchthat the video may be transmitted in an uncompressed form such that somuch data is transmitted each second that bootlegging the content isessentially untenable.

Regardless of the particular application, the present invention makesthe following critical observation about 60 GHz wireless links. Asunderstood herein, it is sometimes necessary for a master component(such as a microcontroller) in the source of data to read and writesystem information to a slave component (such as a register) in thedisplay for control purposes using an appropriate protocol such as theprotocol used by DCI/HDMI. Typically, the master writes data to andreads data from register locations in the slave, and several slaves canbe used, each with its own address. As an example, it might be necessaryfor a master in the source to write security information as might berelated to the above-mentioned HDCP to one or more slaves in thedisplay.

As further understood herein, it is desirable that reads and writesbetween master and slave occur in near real time, particularly in thecase of encryption key exchange that is necessary to support decryptionof video being played. The present invention critically recognizes thatthis is a challenge in wireless applications and in particular ineffecting reads in wireless applications, because the read request mustbe transmitted across the wireless link from master to slave, acted on,and then requested data returned from slave to master over the link,potentially introducing unwanted latency.

SUMMARY OF THE INVENTION

A multimedia display system includes a source system of multimedia dataand a display system of multimedia data. The display system includes adisplay, and the source system and display system communicate wirelesslywith each other. The source system has a master writing data to a slavein the display system, and a slave simulator is in the source system andmirrors at least a portion of the slave written to by the master. Withthis feature, read commands from the master can be satisfied from theslave simulator without sending the read command over the wireless link.

A master simulator may be provided in the display system incommunication with the slave to update the slave simulator with changesin the slave. To this end, a first shadow memory can be provided in theslave simulator and a second shadow memory can be provided in the mastersimulator, with the master simulator operating in an automatic loop tocompare data in the slave to data in the second shadow memory and basedthereon updating the first shadow memory.

The multimedia may be, in non-limiting implementations, Digital VisualInterface (DVI) multimedia and/or High Definition Multimedia Interface(HDMI) multimedia. The wireless link may be in the 60 GHz band, and thedata transmitted between the master and the slave can be High-BandwidthDigital Content Protection (HDCP) data, extended display identificationdata (EDID), or other data. In non-limiting embodiments the master isimplemented by a microcontroller and the slave is implemented by a dualport RAM having registers. Data can be transmitted between the masterand the slave using I²C protocol.

In another aspect, a system for displaying multimedia from a sourcesystem on a display system in wireless communication with the sourcesystem using a wireless link includes means for writing informationuseful in displaying the multimedia from a master at the source systemto a slave at the display system. The system also includes means forsatisfying subsequent read commands from the master for the data from aslave simulator at the source system without sending the read commandover the wireless link.

In yet another aspect, a method for displaying multimedia from a sourceon a display includes wirelessly transmitting the multimedia from thesource to the display using a 60 GHz wireless link, and writing data toa slave at the display from a master at the source using a wirelesslink. The method also includes periodically polling the slave forchanges. Any changes are sent, over the wireless link, to at least oneshadow memory at the source, so that the shadow memory mirrors contentsof the slave. Read commands from the master addressed to the slave areimmediately executed from the shadow memory.

The details of the present invention, both as to its structure andoperation, can best be understood in reference to the accompanyingdrawings, in which like reference numerals refer to like parts, and inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a non-limiting exemplaryimplementation of the present system;

FIG. 2 is a block diagram of the master and slave components;

FIG. 3 is a flow chart of the write logic; and

FIG. 4 is a flow chart of the read preparation logic.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring initially to FIG. 1, a system is shown, generally designated10, which includes a source 12 of baseband multimedia data, and inparticular high definition (HD) digital video with audio. The source 12may be a DVD player, laptop computer or other multimedia computer orserver. Or, it can be a satellite, broadcast, or cable receiver, or settop box or other multimedia source, such as a video receiver, ATSCtuner, or other computer.

The source 12 sends multiplexed multimedia data over lines 14 to a mediareceiver 16. The media receiver 16 may be a set-top box that can includea High Definition Multimedia Interface (HDMI) transmitter 18. The HDMItransmitter 18 employs HDMI protocols to process the multimedia data by,among other things, encrypting the data using High-Bandwidth DigitalContent Protection (HDCP) and supporting TV resolutions such as 16×9display ratios.

The HDMI transmitter 18 can send HDCP-encrypted multimedia data over acable or other wire 19 to a Digital Visual Interface (DVI) receiver 20.According to the present invention, the DVI receiver 20 uses DVIprotocols to process the received data. As part of the processing theHDMI transmitter 18 multiplexes the video and multiplexes the audiowithin the video data stream. This can be done by multiplexing the audiointo the vertical blanking interval (VBI) of the video or it can be doneusing the trailing edge of a clock signal, or by other means. The DVIreceiver 20 demultiplexes the video while passing through the audiomultiplexed within the data stream. In any case, at no time need the DVIreceiver 20 decrypt or re-encrypt the stream.

The encrypted multimedia data from the VBI receiver 20 is sent to aprocessor 22, such as an application specific integrated circuit (ASIC)or field programmable gate array (FPGA). The processor 22 processes thedata for wireless transmission by a wireless transmitter 24 over atransmitting antenna 26. The processor 22 can, among other things,re-multiplex twenty four lines of video and control signals as might bepresent on twenty four multiplex lines 28 into two signals such as mightbe required to support QPSK modulation. Additional control signals forthe display may also be multiplexed within the video data stream. Also,error correction may be implemented that is appropriate for wirelesstransmission in accordance with wireless transmission principles knownin the art.

In any case, the encrypted multimedia data is wirelessly transmittedover a wireless link 30 to a receiver antenna 32, which routes the datato a wireless receiver 34. In accordance with present principles, thelink 30 carries a frequency which is sufficiently high that the signalon the link substantially cannot be received outside the room. Also,multimedia may be transmitted in an uncompressed form on the link 30such that so much data is transmitted each second that bootlegging thecontent is essentially untenable, although some data compression lesspreferably may be implemented. The data may also be transmitted incompressed form if desired. The transmitter 24 and receiver 34 (and,hence, link 30) preferably operate at a fixed (unvarying, single-only)carrier frequency of approximately sixty GigaHertz (60 GHz), and morepreferably in the range of 59 GHz-64 GHz, and the link 30 has a datarate, preferably fixed, of at least two Giga bits per second (2.0 Gbps).When DQPSK is used the data rate may be 2.2 Gbps, and the link may havea data rate of approximately 2.5 Gbps. The link may have a fixedbandwidth of two and half GigaHertz (2.5 GHz).

With this in mind, it may now be appreciated that the wirelesstransmitter 24 preferably includes an encoder for encoding in accordancewith principles known in the art. The encoded data is modulated atapproximately 60 GHz by a 60 GHz modulator and upconverted by anupconverter for transmission over the link 30 at about 60 GHz. Using theabove-described wide channel and a simpler modulation scheme such as butnot limited to DQPSK, QPSK, BPSK or 8-PSK, a high data rate yet simplesystem can be achieved. For example, when DQPSK is used, a data rate oftwice the symbol rate can be achieved. For 8-PSK a data rate of 3.3 Gbpsmay be achieved.

It may further be appreciated that the wireless receiver 34 includescircuitry that is complementary to the wireless transmitter 24, namely,a downconverter, a 60 GHz demodulator, and a decoder. In any case, thedata from the wireless receiver 34 is sent to a processor 36 for errorcorrection and re-multiplexing as appropriate for use by a DVItransmitter 38. The processor 36 can also demultiplex any controlsignals for the display from within the video data as might benecessary. The DVI transmitter 38 operates in accordance with DVIprinciples known in the art to process the encrypted multimedia withoutever decrypting it, and to send the multimedia data over a cable orother wire 39 to a HDMI receiver 40 that may be part of a media player42, such as a DVD player or TV or other player. The HDMI receiver 40decrypts the multimedia data in accordance with HDCP principles anddemultiplexes the audio data from the video data. The multimedia contentmay then be displayed on a display 44, such as a cathode ray tube (CRT),liquid crystal display (LCD), plasma display panel (PDP), or TFT, orprojector with screen, etc.

According to the present invention, the DVI receiver 20, processor 22,and wireless transmitter 24 may be contained on a single chip, or onseparate substrates. Indeed, the DVI receiver 20, processor 22, andwireless transmitter 24 may be integrated into the media receiver 16.Likewise, the wireless receiver 34, processor 36, and DVI transmitter 38may be implemented on a single chip and may be integrated into the mediaplayer 42 if desired. In any case, the media receiver 16 and mediaplayer 42 and respective components preferably are co-located in thesame space, owing to the preferred 60 GHz wireless transmissionfrequency, which very limited ability to penetrate walls.

Because DVI components are used in the wireless portion of thecommunication path between the media receiver 16 (e.g., a set-top box)and the media player 42 (e.g., a TV or DVD player) in the non-limitingembodiment shown, no encryption keys (or concomitant licenses) arerequired for this portion. Also, because the multimedia is neverdecrypted in the wireless portion established between the DVI components20, 38 inclusive, little or no regulatory or data rights concerns areimplicated.

FIG. 2 shows the source and slave components of the present invention.It is to be understood that the source components may be implemented by,e.g., the source processor 22 and that the slave components may beimplemented by, e.g., the processor 36 of the sink, i.e., of thereceiver.

The source components include a master 46 that may be implemented by asuitable microcontroller. The master 48 communicates over wires with aslave simulator 48 that includes a master-side shadow memory 50, whichmay be implemented by, e.g., a dual port RAM. In turn, the slavesimulator 48 communicates over a wireless link 52 (such as the wirelesslink discussed above) with a master simulator 54, and the mastersimulator 54 has a slave-side shadow memory 56 and logic 58 forexecuting the methods below. The master simulator 54 communicates overwires with a slave 60, it being understood that the master simulator 54is essentially logically identical to the master 46 and that the slavesimulator 48 is essentially logically identical to the slave 60. Themaster simulator 54 may be implemented by a microcontroller, and theslave simulator 48 and slave 60 can accept read and write commands inregister locations. For instance, security information such as but notlimited to encryption keys can be written, using the logic below, by themaster 46 to the slave 60 and can be read by the master 46 from theslave 60, with the information in the slave 60 being useful by theabove-described receiver (slave-side) components for presentingmultimedia from the source 12. Accordingly, the shadow memories 50, 56mirror what is in the registers of the slave 60.

FIG. 3 shows the write logic of the present invention. At block 62 themaster 46 asserts a string of bits that provide the address of the slave60 desired to be used, sub-address (e.g., of the registers desired to beused in the slave 60), and data bytes. This information is captured withappropriate handshakes, wrapped in wireless protocol, and sent throughthe slave simulator 48 to the slave side master simulator 54 over thewireless link 52. The write command is received by the master simulator54 at block 66 and executed by writing the data to the slave 60 at block68. The initially-written data can be stored in the shadow memories 50,56 if desired, prior to the master simulator 54 executing the readpreparation logic in FIG. 4. In any case, after the write has beencompleted to the slave 60, the receiver side (sink) componentsacknowledge completion of the write to the source transmitter (source)side in accordance with write principles of e.g., the above-mentionedI²C protocol.

As recognized herein, the master 46 expects a substantially immediateresponse to read commands, and insufficient time may be available tosend a read request over the wireless link and receive back a reply.This is the problem that the shadow memories and simulators discussedherein resolve. More specifically, referring now to FIG. 4, because theinformation in the slave 60 might change for various reasons, the mastersimulator 54 maintains the shadow memories 50, 56 current byperiodically executing the logic at block 70, wherein a register in theslave 60 is read and compared, at decision diamond 72, to thecorresponding data that is mirrored in the shadow memory 56 of themaster simulator 54. If the data is the same the logic loops back toblock 70 to test the next register of the slave 60.

However, when a change is detected in the slave 60, the logic moves fromdecision diamond 72 to block 74, wherein the shadow memory 56 of themaster simulator 54 is updated. Proceeding to block 76, the mastersimulator 54 sends the update to the slave simulator 48 so that theshadow memory 50 is updated. It will readily be appreciated that if themaster 46 subsequently issues a read command, it is immediately executedfrom the slave simulator 48, which returns a response to the master 46without the command and response having to transit the wireless link 52.All protocol timing is maintained between the master 46 and the slavesimulator 48, so that it appears to the master 46 that it is accessingthe slave 60.

The polling logic of FIG. 4 may be implemented by polling through allpossible sub-addresses of the slave 60, or polling only thesub-addresses known to be volatile, or some combination thereof. Thus,in some implementations, the locations in the slave 60 that are ofinterest to the master 46 can be learned by the master simulator 54 byobserving which slave 60 addresses are being read by the master 46, andthese locations may be polled exclusively or simply more frequently thanother locations. Also, the logic above can be extended to more than onedata type and/or device, e.g., extended display identification data(EDID) in a DVI display can be written and read using the above logic,as well as HDCP key exchanges and other data, all of which can besupported.

The above logic can be executed by one or more of the processors herein,all of which are non-limiting examples of various means for satisfyingwrites and read requests from the master to the slave.

While the particular METHOD AND SYSTEM FOR PROCESSING WIRELESS DIGITALMULTIMEDIA as herein shown and described in detail is fully capable ofattaining the above-described objects of the invention, it is to beunderstood that it is the presently preferred embodiment of the presentinvention and is thus representative of the subject matter which isbroadly contemplated by the present invention, that the scope of thepresent invention fully encompasses other embodiments which may becomeobvious to those skilled in the art, and that the scope of the presentinvention is accordingly to be limited by nothing other than theappended claims, in which reference to an element in the singular is notintended to mean “one and only one” unless explicitly so stated, butrather “one or more”. It is not necessary for a device or method toaddress each and every problem sought to be solved by the presentinvention, for it to be encompassed by the present claims. Furthermore,no element, component, or method step in the present disclosure isintended to be dedicated to the public regardless of whether theelement, component, or method step is explicitly recited in the claims.No claim element herein is to be construed under the provisions of 35U.S.C. §112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or, in the case of a method claim, theelement is recited as a “step” instead of an “act”. Absent expressdefinitions herein, claim terms are to be given all ordinary andaccustomed meanings that are not irreconcilable with the presentspecification and file history.

1. A method for displaying multimedia from a source on a display,comprising: wirelessly transmitting the multimedia from the source tothe display using a 60 GHz wireless link; writing data to a slave at thedisplay from a master at the source using a wireless link; periodicallypolling the slave for changes; sending, over the wireless link, thechanges to at least one shadow memory at the source, so that the shadowmemory mirrors contents of the slave; and immediately executing, fromthe shadow memory, read commands from the master addressed to the slaveregardless of communication protocol being used.
 2. The method of claim1, wherein the shadow memory is a first shadow memory associated with aslave simulator, at least one master simulator in the displaycommunicating with the slave to update the slave simulator with changesin the slave.
 3. The method of claim 2, comprising a second shadowmemory in the master simulator, the master simulator operating in anautomatic loop to compare data in the slave to data in the second shadowmemory and based thereon updating the first shadow memory.
 4. The methodof claim 1, wherein the multimedia is at least one of: Digital VisualInterface (DVI) multimedia, and High Definition Multimedia Interface(HDMI) multimedia, and the data transmitted between the master and theslave is at least one of: High-Bandwidth Digital Content Protection(HDCP) data, and extended display identification data (EDID).
 5. Themethod of claim 1, wherein data is transmitted between the master andthe slave at least in part using I²C protocol.
 6. A method fordisplaying multimedia from a source on a display, comprising: wirelesslytransmitting the multimedia from the source to the display using a 60GHz wireless link; writing data to a slave at the display from a masterat the source using a wireless link; periodically polling the slave forchanges; sending, over the wireless link, the changes to at least afirst shadow memory at the source, so that the first shadow memorymirrors contents of the slave; and immediately executing, from the firstshadow memory, read commands from the master addressed to the slave, asecond shadow memory being in the master simulator, the master simulatoroperating in an automatic loop to compare data in the slave to data inthe second shadow memory and based thereon updating the first shadowmemory.
 7. The method of claim 6, wherein the shadow memory is a firstshadow memory associated with a slave simulator, at least one mastersimulator in the display communicating with the slave to update theslave simulator with changes in the slave.
 8. The method of claim 6,wherein the multimedia is at least one of: Digital Visual Interface(DVI) multimedia, and High Definition Multimedia Interface (HDMI)multimedia, and the data transmitted between the master and the slave isat least one of High-Bandwidth Digital Content Protection (HDCP) data,and extended display identification data (EDID).
 9. The method of claim6, wherein data is transmitted between the master and the slave at leastin part using I²C protocol.